Subject: Re: [PATCH net-next 0/8] tg3: Bugfixes and updates

From: "Matt Carlson" <[email-masked]>
Date: Fri, 1 Oct 2010 10:25:45 -0700

On Fri, Oct 01, 2010 at 12:26:28AM -0700, David Miller wrote:
> From: "Matt Carlson" <[email-masked]>
> Date: Thu, 30 Sep 2010 13:34:29 -0700
> 
> > This patchset implements some bugfixes, removes the 5724 device
> > ID and introduces extended rx buffer rings.
> 
> All applied....
> 
> But really, I want to hear some real justification for a 2048 entry RX
> ring at gigabit speeds.  I even think 512 is way too large for gigabit
> parts.

I don't have any personal experience where a larger ring size could
benefit.  However, I have heard of situations in the past where people
have said increasing the amount of rx buffers available has smoothed
over some bursty traffic / cpu usage patterns.  These people really did
want more than 512 rx buffers.

> Any machine that gets one of these newer 5717 parts does not need that
> much queueing, and too deep queues tend to hurt locality and thus
> performance.

Good point.  I'll see if we can scale the BD ring size based on the
number of rx buffers the administrator has configured.